Comparison between histopathologic findings and indocyanine green angiographic findings in Lewis rats with experimental autoimmune uveoretinitis.

PURPOSE Recently, indocyanine green angiography (IA) was used to examine chorioretinal circulation in posterior uveitis in humans, and abnormal IA findings were reported. However, choroidal pathologic examination in conjunction with these abnormal IA findings has rarely been done. Experimental autoimmune uveoretinitis (EAU) is a model for posterior uveitis in humans. The purpose of this study was to correlate abnormal IA findings in Lewis rats with EAU with pathologic findings. METHODS Eleven male Lewis rats were immunized with bovine S-antigen in complete Freund's adjuvant with Bordetella pertussis. After immunization, IA was performed by using a scanning laser ophthalmoscope. Eyes with abnormal IA findings were enucleated and examined histopathologically. RESULTS Demonstrated leakage from retinal vessels at the initial stage of disease; a decrease of background fluorescence and of the number of moderate and large vessels of the choroid, and leakage from choroidal vessels at the progressive stage; and hypofluorescent areas at the late stage. Histopathologic examination at the initial, progressive, and late stages revealed inflammation of the inner layers of the retina, a large number of inflammatory cells in the thickened retina and choroid, and impaired choroidal capillaries, respectively. CONCLUSION Since a correlation between pathologic findings and IA findings was demonstrated in Lewis rats with EAU, IA may be useful for evaluating the severity of uveitis in humans.